The Flora of Mt. Yakeyama
The hot and highly acidic conditions of Mt. Yakeyama’s crater make for a desolate environment. But even in these harsh surroundings, plants adapted to high-acid settings gradually establish themselves. The first to take root in such an environment is wavy hair-grass, which grows in a ring around the crater’s slopes. Once the slopes become stable, sedge begins to grow. On slopes with late snowmelt and high moisture, fringed galax and other plants grow in large clusters. They are then surrounded by crowberry, marsh tea, Hakusan rhododendron, and other shrubs adapted to highly acidic environments.
The summit area features a crater approximately 1 kilometer in diameter, as well as the rugged lava dome called Onigajo. Roughly 1 kilometer to the east lies Mosen Pass, where wildflower meadows blanket the landscape. Japanese crowberry, lingonberry and alpine azalea are just some of the plants to be found here.
In areas around the foot of the mountain where volcanic gas vents abound, like Tamagawa Onsen and Goshogake, June marks the start of the blooming season for several rare types of plants, beginning with white marsh-tea flowers. The highly acidic water that gushes from the hot springs in spots around sulfur-spewing fumaroles creates a challenging environment for plants, but only a short distance away, communities of lichen, sedge, crowberry, and Japanese wintergreen flourish.